Isoforms Of Hepatocyte Growth Factor Research Articles

HEPATOCYTE GROWTH FACTOR FOR WALKING PERFORMANCE IN PERIPHERAL ARTERY DISEASE.

VM202 is a plasmid encoding two isoforms of hepatocyte growth factor (HGF). In preclinical studies, HGF stimulated angiogenesis and muscle regeneration. This preliminary clinical trial tested the hypothesis that VM202 injections in gastrocnemius muscle would improve walking performance in people with mild to moderate and symptomatic lower extremity peripheral artery disease (PAD). In a double-blind clinical trial, people with PAD were randomized to gastrocnemius muscle injections of either 4 mgs of VM202 or placebo every 14 days for four doses. The primary outcome was 6-month change in 6-minute walk distance. Secondary outcomes included 3-month change in treadmill walking time and gastrocnemius muscle biopsy measures. In this preliminary trial, statistical significance was pre-specified as a one-sided P value <0.10. 39 participants with PAD (64.1% Black, 28.2% female) were randomized. Adjusting for age, race, smoking, and baseline performance, VM202 did not improve 6-minute walk at 6-month follow-up, compared to placebo (-13.5 meters, 90% confidence interval (CI): -38.5,+∞). At 3-month follow-up, VM202 improved maximum treadmill walking time (+2.38 minutes (90% CI: +1.08, +∞), P=0.014) and increased central nuclei abundance in gastrocnemius muscle (+5.86, 90% CI: +0.37,+∞, P=0.088), compared to placebo. VM202 did not significantly improve pain-free walking distance (difference: +0.30 minutes, 90% CI:-1.10,+∞, P=0.39), calf muscle perfusion (difference: +1.80 ml/minute per 100 g tissue, 90% CI: -3.80,+∞, P=0.33), or the WIQ distance score (difference: +2.02, 90% CI: -8.11,+∞, P=0.40). In post-hoc analyses, VM202 significantly improved 6-minute walk in PAD participants with diabetes mellitus at 6-month follow-up (+34.19 (90% CI: 4.04,+∞), P=0.075), but had no effect in people without diabetes (interaction P value=0.079). These data do not support gastrocnemius injections of VM202 to improve 6-minute walk in PAD. Secondary outcomes suggested potential benefit of VM202 on skeletal muscle measures and treadmill walking, while post-hoc analyses suggested benefit in PAD participants with diabetes.

Nine-year follow-up of patients receiving recombinant human hepatocyte growth factor nude plasmid DNA for critical limb ischemia: Updated safety and efficacy results

Abstract: CONTEXT: NL003 is a plasmid engineered to simultaneously express two isoforms of hepatocyte growth factor. The Phase II clinical trial shows that intramuscular injection of NL003 in the affected limb of patients with critical limb ischemia (CLI) is safe and could alleviate pain and promote ulcer healing. The purpose of this study was to evaluate the long-term safety and efficacy of NL003. METHODS: A total of 108 participants were evaluated: 32 in the placebo group and 76 in the NL003 group. The primary endpoint was 5-year amputation-free survival and the secondary endpoints were pain, ulcer, and adverse reactions. RESULTS: During a mean follow-up period of 10.4 years, the 5-year amputation-free survival rate was 67.1% (51/76) in the NL003 group and 37.5% (12/32) in the placebo group (P &lt; 0.05). The median amputation-free survival was 9.53 years in the NL003 group and 4.51 years in the placebo group. There was no significant difference in the rates of major amputation between the two groups (21.1% vs. 21.9%). Pain relief and ulcer healing tended to favor the NL003 group. No serious adverse reactions such as gene integration and tumor were found during the follow-up. CONCLUSIONS: NL003 has a favorable long-term safety profile and may provide long-term benefit for patients with CLI.

Gabapentin inhibits the analgesic effects and nerve regeneration process induced by hepatocyte growth factor (HGF) in a peripheral nerve injury model: Implication for the use of VM202 and gabapentinoids for peripheral neuropathy

Hepatocyte growth factor (HGF) is a multifunctional protein that plays a critical role in the angiogenic, neurotrophic, antifibrotic, and antiapoptotic activities of various cell types. It has been previously reported that intramuscular injection of pCK-HGF-X7 (or VM202), a plasmid DNA designed to express both native isoforms of human HGF (Pyun et al., 2010), significantly reduced the level of neuropathic pain in clinical studies as well as in a variety of animal models. In clinical studies, it has been observed that pCK-HGF-X7 appeared to give much higher pain-relieving effects in subjects not taking pregabalin or gabapentin, α2δ1 calcium channel blockers frequently prescribed for reducing pain in patients with diabetic peripheral neuropathy. In this study, we tested the effects of gabapentin on HGF-mediated pain reduction and nerve regeneration in vivo. Consistent with the data from clinical studies, gabapentin administration inhibited the pain reduction and axon regeneration effects mediated by HGF expression from pCK-HGF-X7. In the context of nerve regenerative effects, treatment with gabapentin or EGTA, a Ca2+ chelator, inhibited HGF-mediated axon outgrowth of injured sciatic nerves in vivo. Taken together, i.m. injection of HGF-encoding plasmid DNA ameliorated pain symptoms and enhanced the regeneration of injured nerves, and these therapeutic effects of HGF were significantly hindered by gabapentin treatment, suggesting the possible involvement of Ca2+ in the pro-regenerative activities of native HGF derived from treatment with pCK-HGF-X7.

Hepatocyte Growth Factor Isoforms in Tissue Repair, Cancer, and Fibrotic Remodeling.

Hepatocyte growth factor (HGF), also known as scatter factor (SF), is a pleotropic factor required for normal organ development during embryogenesis. In the adult, basal expression of HGF maintains tissue homeostasis and is up-regulated in response to tissue injury. HGF expression is necessary for the proliferation, migration, and survival of epithelial and endothelial cells involved in tissue repair in a variety of organs, including heart, lung, kidney, liver, brain, and skin. The administration of full length HGF, either as a protein or using exogenous expression methodologies, increases tissue repair in animal models of tissue injury and increases angiogenesis. Full length HGF is comprised of an N-terminal hairpin turn, four kringle domains, and a serine protease-like domain. Several naturally occurring alternatively spliced isoforms of HGF were also identified. The NK1 variant contains the N-terminal hairpin and the first kringle domain, and the NK2 variant extends through the second kringle domain. These alternatively spliced forms of HGF activate the same receptor, MET, but they differ from the full length protein in their cellular activities and their biological functions. Here, we review the species-specific expression of the HGF isoforms, their regulation, the signal transduction pathways they activate, and their biological activities.

A PHASE 2, DOUBLE-BLIND, RANDOMIZED, PLACEBO-CONTROLLED, MULTICENTER TRIAL OF THE SAFETY AND EFFICACY OF PLASMID DNA EXPRESSING 2 ISOFORMS OF HEPATOCYTE GROWTH FACTOR IN PATIENTS WITH CRITICAL LIMB ISCHEMIA

Hepatocyte growth factor (HGF) has shown promise in treating patients with critical limb ischemia (CLI). We performed this phase II study to assess the safety and efficacy of the intramuscular (IM) injection of VM202, plasmid DNA expressing 2 isoforms of HGF, in CLI patients. We enrolled 52

Phase 1/2 Open-label Dose-escalation Study of Plasmid DNA Expressing Two Isoforms of Hepatocyte Growth Factor in Patients With Painful Diabetic Peripheral Neuropathy

This study aimed to evaluate the safety and preliminary efficacy of intramuscular injections of plasmid DNA (VM202) expressing two isoforms of hepatocyte growth factor (HGF) in subjects with painful diabetic peripheral neuropathy (PDPN). Twelve patients in three cohorts (4, 8, and 16 mg) received two sets of VM202 injections separated by two weeks. Safety and tolerability were evaluated and the visual analog scale (VAS), the short form McGill questionnaire (SF-MPQ), and the brief pain inventory for patients with diabetic peripheral neuropathy (BPI-DPN) measured pain level throughout 12 months after treatment. No serious adverse events (AEs) were observed. The mean VAS was reduced from baseline by 47.2% (P = 0.002) at 6 months and by 44.1% (P = 0.005) at 12 months after treatment. The VAS scores for the 4, 8, and 16 mg dose cohorts at 6 months follow-up decreased in a dose-responsive manner, by 21% (P = 0.971), 53% (P = 0.014), and 62% (P = 0.001), respectively. The results with the BPI-DPN and SF-MPQ showed patterns similar to the VAS scores. In conclusion, VM202 treatment appeared to be safe, well tolerated, and sufficient to provide long term symptomatic relief and improvement in the quality of life in patients with PDPN.

Abstract 5637: A cellular model of acquired resistance to rilotumumab (AMG 102) in glioblastoma.

Abstract Acquired drug resistance is a long-standing problem of cancer therapeutics. The issue has become even more vexing with the development of highly selective agents; resistance to gefitinib or erlotinib is acquired frequently in lung adenocarcinomas. Thus, anticipating acquired resistance and understanding its basis may help us develop strategies to prevent or circumvent occurrence. Through its receptor tyrosine kinase Met, hepatocyte growth factor (HGF) regulates mitogenesis, motogenesis, and morphogenesis during development and adulthood. HGF/Met signaling also contributes to cancer progression in many malignancies, including glioblastoma. Rilotumumab is a fully human neutralizing monoclonal antibody against HGF tested in multiple Phase 2 clinical trials, including mono therapy in renal cell carcinoma and glioblastoma, as well as combination trials in gastric, colorectal, small cell lung cancers and castrate resistant prostate cancer. To generate a cellular model of acquired resistance to rilotumumab, an HGF/Met dependent human glioblastoma-derived cell line (U87-MG) was grown in rilotumumab (600 nM) for 120 days. Growth rate, HGF secretion, Met content and Met activation state were 10-fold, 10,000-fold, 10-fold and 80-fold higher than the parental cell values, respectively. The HGF and MET coding sequences were normal in both parental and resistant cells. Quantitative PCR studies to determine mRNA levels of all HGF isoforms revealed a dramatic increase in full-length HGF transcript. CGH array studies indicated amplification within both HGF and MET genes. Xenograft studies confirmed that tumor growth was resistant to rilotumumab, however the resistant cell line and tumors remained sensitive to a highly selective Met tyrosine kinase inhibitor, suggesting that resistance was achieved via increased HGF/Met signaling rather than mutation or activation of alternate pathways. Microarray expression analysis demonstrated transcript profiles that were consistent with HGF/Met pathway activation. Thus the molecular basis of acquired resistance in this model differs from those prevalent in: [1] lung cancers treated with EGFR inhibitors and medulloblastomas treated with hedgehog inhibitors, where most cases acquire secondary mutations in the targeted kinase; [2] breast cancers treated with HER2 inhibitors, where PTEN loss, p27 downregulation, and activation of other receptors are primary causes; or [3] malignant melanoma treated with BRAF inhibitors, where increased signaling via multiple pathways lead to PI3K- and/or MEK-mediated reactivation of the MAPK pathway. In addition to the importance of HGF/Met pathway activity in selecting glioblastoma patients for HGF-targeted therapeutics, our results suggest that monitoring Met pathway activity could provide early indications of acquired resistance to these agents, and that Met kinase inhibitors may still be efficacious when resistance occurs. Citation Format: Fabiola Cecchi, Karen Rex, Joanna Schmidt, Daniel Baker, Michael A. Damore, Angela Coxon, Teresa L. Burgess, Donald P. Bottaro. A cellular model of acquired resistance to rilotumumab (AMG 102) in glioblastoma. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5637. doi:10.1158/1538-7445.AM2013-5637

Intramyocardial transfer of hepatocyte growth factor as an adjunct to CABG: phase I clinical study

The purpose of this phase I clinical trial was to evaluate the safety, tolerability and potential efficacy of VM202, naked DNA expressing two isoforms of hepatocyte growth factor, as an adjunct therapy to coronary artery bypass grafting (CABG) in patients with ischemic heart disease (IHD). Nine patients were assigned to receive increasing doses (0.5 to 2.0 mg) of VM202 injected into the right coronary artery (RCA) territory following completion of CABG for the left coronary artery territory. Patients were evaluated for safety and tolerability, and changes in myocardial functions were monitored via echocardiography, cardiac magnetic resonance imaging and myocardial single photon emission computed tomography throughout 6-month follow-up period. No serious complication related to VM202 was observed throughout the 6-month follow-up period. Global myocardial functions (wall motion score index, P=0.0084; stress perfusion, P=0.0002) improved during the follow-up period. In the RCA region, there was an increase in the stress perfusion (baseline vs 3-month, P=0.024; baseline vs 6-month, P=0.024) and also in the wall thickness of the diastolic and systolic phases. Intramyocardial injection of VM202 can be safely used in IHD patients with the tolerable dose of 2.0 mg. In addition, VM202 might appear to have improved regional myocardial perfusion and wall thickness in the injected region.

Targeted Disruption of Heparan Sulfate Interaction with Hepatocyte and Vascular Endothelial Growth Factors Blocks Normal and Oncogenic Signaling

Hepatocyte growth factor (HGF) and vascular endothelial cell growth factor (VEGF) regulate normal development and homeostasis and drive disease progression in many forms of cancer. Both proteins signal by binding to receptor tyrosine kinases and heparan sulfate (HS) proteoglycans on target cell surfaces. Basic residues comprising the primary HS binding sites on HGF and VEGF provide similar surface charge distributions without underlying structural similarity. Combining three acidic amino acid substitutions in these sites in the HGF isoform NK1 or the VEGF isoform VEGF165 transformed each into potent, selective competitive antagonists of their respective normal and oncogenic signaling pathways. Our findings illustrate the importance of HS in growth factor driven cancer progression and reveal an efficient strategy for therapeutic antagonist development.

A phase I clinical study of naked DNA expressing two isoforms of hepatocyte growth factor to treat patients with critical limb ischemia

The purpose of the present phase I clinical trial was to evaluate the safety, tolerability, and preliminary efficacy of naked DNA therapy expressing two isoforms of hepatocyte growth factor (pCK-HGF-X7) in critical limb ischemia (CLI) patients. Twenty-one patients with CLI were consecutively assigned to receive increasing doses (cohort I: 4 mg; cohort II: 8 mg; cohort III: 12 mg; and cohort IV: 16 mg) of pCK-HGF-X7, which was administered into the ischemic calf and/or thigh muscle at days 1 and 15. A safety and tolerability evaluation and measurement of pain severity score using a visual analog scale (VAS), ulcer status, transcutaneous oxygen (TcPO(2) ) and ankle-brachial index (ABI) were performed throughout a 3-month follow-up period. No serious adverse events were observed in any of the 21 patients for the 3-month follow-up period. A significant reduction in pain was observed in the treated patients, with the mean VAS decreasing from 5.95-1.64 (p < 0.001). The mean ABI value increased from 0.49-0.63 (p = 0.026) at 3-month follow-up. The mean TcPO(2) value on the dorsum of the foot, the anterior calf and posterior calf significantly increased from 28.25-39.28 mmHg (p = 0.012), from 22.00-30.63 mmHg (p = 0.046) and 32.05-47.19 mmHg (p = 0.001) at 3-month follow-up, respectively. Wound healing improvement was observed in the six of nine patients that had an ulcer at baseline. These results support the performance of a phase II randomized controlled trial with pCK-HGF-X7.

Enhanced cardioprotective effects by coexpression of two isoforms of hepatocyte growth factor from naked plasmid DNA in a rat ischemic heart disease model

The therapeutic potential of pCK-HGF-X7, a naked DNA designed to express two isoforms of hepatocyte growth factor (HGF(723) and HGF(728) ), was studied in the rat ischemic heart disease model. First, the kinetics of gene expression was examined by injecting pCK-HGF-X7 DNA into the rat heart. Second, the cardioprotective effects were compared between the two naked DNA constructs, expressing a single (HGF(728) ) or both isoforms (HGF(728) and HGF(723) ) of HGF, in the rat ischemic heart disease model. The ischemic injury to the rat heart was created by ischemia-reperfusion in the anterior descending artery. The respective naked DNA constructs were injected into the anterior wall of the rat heart with the ischemia-reperfusion injury. Cardiac function, capillary density and anti-fibrotic activity were compared between the two naked DNA constructs. The intramyocardial administration of pCK-HGF-X7 resulted in transient and localized HGF expression for 3 weeks. At its peak, approximately 678 pg (per mg of tissue protein) of HGF was produced in the injected heart without an increase of HGF protein level in other tissues, and serum. pCK-HGF-X7 more efficiently improved the left ventricular ejection fraction and the systolic anterior wall thickness, increased the capillary density, and inhibited myocardial fibrosis, in a statistically significant manner, compared to the identical vector encoding HGF(728) only. These results demonstrate that transfer of the genomic-cDNA hybrid expressing both isoforms of the HGF gene might provide higher therapeutic effects than the cDNA sequence producing HGF(728) alone in the treatment of ischemic heart disease.

A hepatocyte growth factor antagonist engineered by site-directed mutagenesis.

10528 Background: Hepatocyte growth factor (HGF) stimulates cell proliferation, motility, and morphogenesis upon binding to the receptor tyrosine kinase Met and cell surface heparan sulfate (HS) glycans. NK1 is a truncated HGF isoform consisting of the N-terminal (N) and first kringle (K1) domains of full-length HGF that stimulates all major HGF biological activities. Within NK1, the N domain contains the HS binding site, while K1 contains the primary determinants of Met binding. Methods: To understand the role of HS in ligand-receptor interaction and biological signaling, we identified three putative HS binding residues in N domain (K60, K62 and R73), generated opposite charge mutations at these positions in NK1, and characterized the recombinantly expressed proteins biochemically and biologically. Results: Nuclear magnetic resonance analysis of mutant and wild type (WT) proteins revealed that no significant structural alterations were introduced by the mutations. The binding of each of the mutant proteins to immobilized heparin was reduced relative to WT, most profoundly in the combined triple mutant (3M). 3M also lacked biological activity, and competitively antagonized HGF activity in normal cells. 3M also potently inhibited oncogenic Met signaling. Soft agar colony formation by HGF-driven tumor cell lines was reduced 50% in the presence of 70 nM 3M protein and abolished in the presence of 300 nM, relative to untreated controls. Similar levels of inhibition were observed using the Met inhibitor PHA665752 at the same concentrations. Ectopic 3M expression in these tumor lines dramatically reduced their growth rate as xenografts in mice and was associated with reduced tumor phosphoMet content. HGF-driven experimental metastasis by B16 cells was blocked by ectopic 3M expression, or by daily intraperitoneal (IP) administration of purified recombinant 3M. Conclusions: Our results show that HS binding is critical for HGF-driven mitogenesis, motogenesis, tumor growth and metastasis, and inhibition of these activities by 3M validates a novel strategy for developing antagonists of the HGF signaling pathway and potentially those of other HS-binding ligands.

Safety of a non-viral plasmid-encoding dual isoforms of hepatocyte growth factor in critical limb ischemia patients: a phase I study

We aimed to evaluate in a phase I dose-escalation study, the safety of intramuscular injections of a novel non-viral plasmid DNA expressing two isoforms of human hepatocyte growth factor (HGF) (VM202) in patients with critical limb ischemia (CLI). In total, 12 patients with CLI and unsuitable for revascularization were consecutively assigned to increasing doses (2 to 16 mg) of VM202 administered into the ischemic calf muscle at days 1 and 15. Patients were evaluated for safety and tolerability, changes in ankle- and toe brachial index (ABI and TBI), and pain severity score using a visual analog scale (VAS) throughout a 12-month follow-up period. Median age was 72 years and 53% of the patients were male. VM202 was safe and well tolerated with no death during the 12-month follow-up. Median ABI and TBI significantly increased from 0.35 to 0.52 (P=0.005) and from 0.15 to 0.24 (P=0.01) at 12 months follow-up. Median VAS decreased from 57.5 to 16.0 mm at 6 months follow-up (P=0.03). In this first human clinical trial, VM202, which expresses two isoforms of human HGF, appear to be safe and well tolerated with encouraging clinical results and thus supports the performance of a phase II randomized controlled trial.

Multiple Myeloma Plasma Cell Expression of Hepatocyte Growth Factor mRNA Isoforms Correlates with Overall Survival In Myeloma Patients

AbstractAbstract 4983 Background:Full length Hepatocyte growth Factor (HGF) (consisting of four “kringle”-domains) is known to be produced by multiple myeloma plasma cells (MM PC) in vivo and HGF is among the 70 most up regulated genes in MM. Elevated serum levels of HGF are known to be an adverse prognostic factor and recently, MM PC expression of the HGF receptor cMET has been shown to be an adverse prognostic factor. Functionally, HGF inhibits osteoblastogenesis in vitro and promotes migration of MM PC. So far, studies on HGF and its impact in MM have focused on measuring full-length or all isoforms of HGF expression. However, naturally occurring shorter isoforms of HGF (known as NK1 and NK2) are known to work as partial inhibitors of full-length HGF (Otsuka et al, Mol and Cell Biol, 2000). We examined the HGF isoforms and cMET expression at the mRNA level in isolated MM PC of >150 newly diagnosed patients with MM, 18 MGUS patients and 8 healthy volunteers (HV) and associated it to overall survival (OS) and degree of osteolytic bone disease (OBD). Methods:Aberrant MM PCs (CD38++/CD19-/CD45-/i/CD56-/+/++) were sorted directly into PCR tubes by fluorescence activated cell sorting (FACS) using a FACS Aria (BDIS). In all cases a PC-purity above 98% was obtained. A cDNA archive was generated by global reverse transcription. By using a polyadenylating step 5x-oligo(dT)-transcript-poly(A)-3xcDNA were generated and finally amplified by PCR using a sequence independent X-(dT)24 primer. The conditions of the reverse transcriptase reaction is designed to limit the size of the first strand cDNA to 300–700 bases, which leads to a more uniform and unbiased amplification. Isoform specific primers were designed using the Primer Express program and experimentally tested. The HGF version covered full-length HGF (transcript variant 1 and 3), HGF2 covered the 2 kringle domain versions (transcript variant 2 and 4) and HGF5 covered the 1 kringle domain version (transcript variant 5). cMET only exists in one isoform. Quantitative PCR was performed using β-actin as internal reference gene, using the δCt method. Determination of positivity or negativity was made from a cut-off-value at 10E-05. OBD was evaluated by standard radiographic methods. The MM patients were treated with either high-dose melphalan with ASCT or melphalan-prednisone according to age recommendations. Results: At least one of the HGF isoforms were found to be expressed in PCxs from 43% of MM patients compared to 32% of MGUS patients, and 0% of HV. Full length HGF was expressed in 17 %, HGF2 in 29%, and HGF5 in 26% of the MM patients. Expression of any HGF variant was associated to an adverse OS (p=0.04) (Fig. 1). The quantitative expression of the transcript variant 5 associated negatively to OS (p=0.02), while expression of the other specific isoforms showed no association to OS. Thus, somehow surprisingly, MM PC expression of the shorter isoform of HGF (HGF5) was more predictive of poor prognosis.A tendency towards elevated expression of full-length HGF in patients with no OBD compared to limited or advanced was observed but did not reach statistically significance (p=0.13). Pre-liminary analysis of cMET expression data showed no correlation between MM PC cMet expression and degree of OBD. Further data on cMet will be presented at the meeting. [Display omitted] Disclosures:No relevant conflicts of interest to declare.

Naked DNA expressing two isoforms of hepatocyte growth factor induces collateral artery augmentation in a rabbit model of limb ischemia

Hepatocyte growth factor (HGF) has been shown to induce angiogenesis in vivo and has potential as a candidate gene for 'therapeutic angiogenesis'. In vivo, two isoforms of HGF, HGF₇₂₃ and HGF₇₂₈, consisting of 723 and 728 amino acids, are generated through alternative splicing between exons 4 and 5, but the biological effects of their coexpression have not yet been elucidated. In this study, we generated a series of genomic-complementary DNA (cDNA) hybrids of the HGF gene by inserting various truncated intron 4 into the junction of exons 4 and 5 of HGF cDNA and analyzed the biological activities of these hybrid constructs. We showed that: (1) the hybrid called HGF-X7, which contained 1502 base pairs of intron 4, could drive a higher level of HGF expression than other hybrid constructs and cDNAs of each isoform alone; (2) the pCK vector was most efficient for the gene expression of HGF-X7; (3) coexpression of both isoforms of HGF could more efficiently induce the migration of human umbilical vein endothelial cell (HUVEC) and of the mouse myoblast cell line C₂C₁₂ myoblasts than a single isoform of HGF and human vascular endothelial growth factor (VEGF)₁₆₅ at a given concentration; (4) intramuscular administration of pCK-HGF-X7 resulted in transient and localized HGF expression in the injected muscle without an increase in the HGF protein levels in other tissues including serum; and (5) intramuscular injection of pCK-HGF-X7 could more efficiently increase the number of angiographically recognizable collateral vessels, as well as improve an intra-arterial Doppler wire-measured blood flow in the rabbit model of hindlimb ischemia when compared with the identical vector encoding VEGF₁₆₅ gene. These results showed that transfer of the genomic-cDNA hybrid of the HGF gene could be used as a potential therapeutic approach to human vascular diseases.

Abstract SY23-03: Oncogenic signal transduction via the hepatocyte growth factor/Met receptor kinase pathway

Abstract SY23-03: Oncogenic signal transduction via the hepatocyte growth factor/Met receptor kinase pathway

309 MR assessment of myocardial perfusion, viability and function after intramyocardial transfer of plasmid expressing two isoforms of hepatocyte growth factor in swine model

Methods In this study the HGF gene was injected intramyocardially in reperfused infarction (2 hr occlusion), for the purpose of evaluating this strategy as a therapeutic approach for protection from LV remodeling. MR imaging was performed at 3 days and 7–8 weeks on a 1.5-T MR clinical scanner (Philips Medical Systems). First pass perfusion, delayed contrast enhancement and cine MR imaging was used in the evaluation. Triphenyltetrazolium chloride (TTC) and histopathological (Masson's trichrome and Biotinylated Bandeiria simplicifolia isolectin B4) stains were utilized to quantify vascular density and myocardial viability. Results The peak signal intensity (SI), extents of hypoenhanced ischemic myocardium and max upslope data in the two groups were not significantly different at 3 days. At 7–8 weeks peak signal intensity was higher and maximum upslope data was steeper in treated animals compared to controls. The extent of hyperenhanced scar was significantly larger in control (13.2 ± 1.6% LV) compared with HGF treated (7.0 ± 0.5% LV) animals. TTC analysis also showed that the extent of scar tissue was significantly larger in control (12.0 ± 1.7%) compared with treated (6.6 ± 0.7% LV, P = 0.04) animals. There was no significant difference between the extent of hyperenhanced scar on MRI and TTC (P = 0.32). The infarction tended to be non-transmural with a residual thicker wall in treated compared with control animals both on MR images and TTC. Control animals showed evidence of LV remodeling, which was reflected by increased end systolic volumes and decline in ejection fraction. Treated animals showed a decrease from in end diastolic (2.15 ± 0.12 to 1.82 ± 0.12, P = 0.008) and end systolic (1.33 ± 0.07 to 1.00 ± 0.08, P = 0.001) volumes. They also showed increased ejection fraction (40.3 ± 1.3 to 45.7 ± 1.8, P = 0.001).

Therapeutic angiogenesis using naked DNA expressing two isoforms of the hepatocyte growth factor in a porcine acute myocardial infarction model☆

We evaluated the potency of therapeutic angiogenesis using intramyocardial injection of naked DNA expressing two isoforms of hepatocyte growth factor (pCK-HGF-X7) in a porcine myocardial infarction model. Four weeks after left anterior descending coronary artery ligation, 14 pigs were allocated to pCK-Null (negative control, n=7) or pCK-HGF-X7 (n=7) treatment groups. Gated myocardial single photon emission computed tomography was performed 4 and 8 weeks following coronary ligation. The effect of pCK-HGF-X7 on capillary density in the gene-injected myocardium was examined by histological analysis using alkaline phosphatase staining. Segmental myocardial perfusion of the underperfused area (< or =70%) from coronary ligation increased in the pCK-HGF-X7 group (p=0.051), without significant differences in changes over time between the two groups (p=0.54). Systolic wall thickening (p=0.001), left ventricular end-diastolic (p=0.045) and end-systolic volumes (p=0.009), and left ventricular ejection fraction (p=0.041) changed in both groups without significant differences in changes over time between the two groups. The increase in the left stoke volume was higher in the pCK-HGF-X7 group than in the pCK-Null group (p=0.008). Histological analysis showed that capillary density was significantly higher in the pCK-HGF-X7 group than the pCK-Null group (p<0.001). Intramyocardial injection of pCK-HGF-X7 induced significant angiogenesis at infarct-border zone, and increased the left ventricular stroke volume probably caused by reverse remodeling process.

Quantitative MR measurements of regional and global left ventricular function and strain after intramyocardial transfer of VM202 into infarcted swine myocardium

Previous studies have shown the beneficial effects of the hepatocyte growth factor (HGF) gene on myocardial perfusion and infarction size but not on the regional strain in relationship to global left ventricular function. A noninvasive magnetic resonance (MR) study was performed to determine the effect of a new HGF gene, VM202, expressing two isoforms of HGF, on regional and global left ventricular function. Pigs (8/group) were divided into three groups: 1) controls without infarction; 2) reperfused, infarcted controls; and 3) infarcted, treated (1 h after reperfusion) with VM202 injected at eight sites. Cine, tagging, and delayed enhancement MR images were acquired at 3 and 50 +/- 3 days after infarction. At 50 days, ejection fraction in infarcted, treated animals increased (38 +/- 1% to 47 +/- 2%, P < 0.01) to the level of controls without infarction (52 +/- 1%, P = 0.16) but decreased in infarcted controls (41 +/- 1% to 37 +/- 1%, P < 0.05). Two-dimensional strain improved in remote, peri-infarcted, and infarcted myocardium. Furthermore, the infarction size was smaller in infarcted, treated animals (7.0 +/- 0.5%) compared with infarcted controls (13.2 +/- 1.6%, P < 0.05). Histopathology showed a lack of hypertrophy in myocytes in peri-infarcted and remote myocardium and the formation of islands/peninsulas of myocytes in infarcted, treated animals but not in infarcted controls. In conclusion, the plasmid HGF gene caused a near complete recovery of ejection fraction and improved the radial and circumferential strain of remote, peri-infarcted, and infarcted regions within 50 days. These beneficial effects may be explained by the combined effects of a speedy and significant infarct resorption and island/peninsulas of hypertrophied myocytes within the infarcted territory but not by compensatory hypertrophy. The combined use of cine and tagging MR imaging provides valuable information on the efficacy of gene therapy.

876. Development of Novel Angiogenic DNA Medicine Using a Genomic/cDNA Hybrid of Hepatocyte Growth Factor Gene

Background Hepatocyte growth factor (HGF) has angiogenic and antifibrotic activity and two isoforms of HGF are naturally expressed by alternative splicing. Here, we developed genomic/cDNA hybrids of HGF gene, which can generate two isoforms of HGF simultaneously and efficiently. We examined therapeutic potential of this novel form of HGF gene both in rabbit ischemic limb disease model and rat ischemic heart disease model. Methods and results We generated a series of genomic/cDNA hybrids of HGF gene.